GB2077745A

GB2077745A - Process of subbing a plastics film with a terpolymer latex for use as photographic support

Info

Publication number: GB2077745A
Application number: GB8114644A
Authority: GB
Original assignee: Nippon Zeon Co Ltd; Fuji Photo Film Co Ltd
Current assignee: Zeon Corp; Fujifilm Holdings Corp
Priority date: 1980-05-15
Filing date: 1981-05-13
Publication date: 1981-12-23
Also published as: JPS57128332A; GB2077745B; US4423089A; JPH0322614B2

Description

1 GB 2 077 745 A 1

SPECIFICATION Process of Subbing a Plastics Film with a Terpolymer Latex, for use as Photographic Support

The present invention relates to a process for applying a so-called subbing layer to a plastic film base prior to application of a photographic hydrophilic organic colloid layer (referred to hereinafter as the photographic layer), such as a silver halide photographic emulsion layer, in order to obtain firm 5 adhesion of said photographic layer to the base.

Hitherto, in order to firmly bond the photographic layer to the plastic film base, two processes have been used, namely (i) a process which comprises applying the photographic layer directly to the plastic film base after the base is subjected to a surface activating treatment, such as a chemical treatment, an electrical discharge treatment, an ultraviolet ray application, etc., and (ii) a process which 10 comprises applying a subbing layer after carrying out a surface activating treatment and applying the photographic layer to the resulting subbing layer.

Such processes have been described, for example, in U.S. Patents 2,698, 241, 2,764,520, 2,864,755, 2,864,756 and 3,475,193 and British Patents 788,365, 804,005 and 891,469.

Of these processes, the process (ii) has been more widely used in general. Particularly, in the case wherein the base is polyethylene terephthalate (referred to as PET, hereinafter) or polystyrene, the photographic layer does not sufficiently bond to the base if a subbing layer is not provided after carrying out the surface activating treatment.

However, the above-described surface activating treatment has various faults. For instance, if the surface of the base is treated with a solvent, surface flatness of the base deteriorates and the residual 20 solvent can have an adverse influence upon the photographic layers, and particularly upon the silver halide emulsion layer(s). Furthermore, in order to obtain sufficient adhesion by the ultraviolet ray application, it is necessary to expose the base at a high temperature above the glass transition temperature during the treatment. Consequently, the surface flatness of the base remarkably deteriorates because of decrease of modulus of elasticity and contraction by heat, etc.

Furthermore, if sufficient adhesion is to be obtained by the corona discharge treatment, it is necessary to carry out the treatment at a high temperature above the glass transition temperature, and consequently the same results as in the case of the ultraviolet ray application are obtained.

Moreover, the surface activating treatment not only causes deterioration of external quality but also has an adverse influence upon the photographic layer because of formation of a very small amount 30 of oligomers and acetaldehyde, etc. Accordingly, it has been desired to provide a subbing process by which the sufficient adhesion can be obtained without carrying out the surface activating treatment or with less degree of the surface activating treatment as far as possible, though required.

As one means therefor, there is a process which comprises incorporating a solvent capable of swelling or dissolving the base in a subbing solution.

As known solvents for polyethylene terephthalate, there are, for example, salicyclic acid, trichloroacetic acid, pyrrole, chloral hydrate, phenol, p-chlorophenol, pyrogallol and resorcinol.

However, these solvents are generally difficult to handle and toxic to the human body. Further, they create problems of environmental pollution. Accordingly, their use is greatly restricted.

For the purpose of overcoming the above-described problems of the prior art, subbing processes 40 using an aqueous dispersion of a polymer latex have been developed in recent times.

Some such subbing processes using an aqueous dispersion of a copolymer composed of (1) a diolefin monomer, (2) one or more vinyl monomers, and, some times, (3) another component, are described in Japanese Patent Applications (OPI) 112326/76, 117617/76, 121323/76, 123139/76 and 139320/76 (the term "OPI" as used herein refers to a "published unexamined Japanese patent 45 application"). Further, the present inventors have studied a blending process described in Japanese Patent Application (OPI) 65422/77 wherein it is intended to obtain desired properties by blending a styrene-butadiene based latex with another latex, and an addition process described in Japanese Patent Application (OPI) 114120/76 wherein it is intended to obtain desired properties by adding additives, e.g. hardeners, to a styrenebutadiene based latex.

- According to these processes, a certain degree of adhesive strength can obtained without causing problems of toxicity and environmental pollution. However, in order to obtain sufficient adhesive strength, it is necessary to carry out a separate intensive heat treatment after application and drying in the subbing step. Accordingly, these processes are disadvantageous in both operation and cost.

For the purpose of overcoming this problem, a subbing process has been studied which comprises applying an aqueous dispersion of a copolymer composed of (i) a diolefin mono'mer and (ii) one or more vinyl monomers, wherein the gel fraction of the copolymer in the aqueous dispersion is less than 80% by weight, as is described in British Patent Application GB 2040730A.

According to this process, sufficient adhesive strength can be obtained under a condition of a low 60 heating temperature during the step of application and drying without causing problems of toxicity and environmental pollution. However, in the case wherein the subbing is carried out using a copolymer having a low gel fraction, there is a problem in that the surface of the subbing layer is easily scratched in the drying step. Such a scratch in the subbing layer can be visually observed through the GB 2 077 745 A 2 photographic emulsion layer after application thereof and development of the film, and is therefore very undesirable.

Accordingly, a first object of the present invention is to provide a subbing process by which the photographic layer firmly bonds to the base without having an adverse influence upon the surface of 5 the subbing layer and without the necessity of subjecting the base to a surface activating treatment.

A second object is to provide a subbing process which comprises firmly bonding the photographic layer to the base with using a non-toxic subbing solution which does not create problems of environmental pollution.

A third object is to provide a subbing process by which sufficient adhesive strength can be obtained even if the subbing treatment is carried out at a comparatively low temperature.

A fourth object is to provide a subbing process by which sufficient adhesive strength is obtained without damaging surface flatness of the base.

A fifth object is to provide a subbing solution which does not require a surface activating treatment, is non-toxic to human bodies, and does not cause environmental pollution problems, by which sufficient adhesion can be obtained even if treated at a comparatively low temperature. 15 A sixth object is to provide photographic light-sensitive materials having a subbing layer formed from the above-described subbing solution.

According to the present invention we provide a subbing process for a photographic film base for a light-sensitive material, comprising applying to a plastics film base a latex (aqueous dispersion) of a copolymer composed of (1) a diolefin monomer, (2) at least one monovinyl monomer, and (3) at least 20 one monomer having two or more vinyl groups, acryioyl groups, methacryloyl group or allyl groups other than the diolefin monomer, the gel fraction of the polymer in the latex being from 50% to 95% by weight.

The cross-linked---gelfraction- is defined below.

In the present invention, as the diolefin monomer composing the copolymer as the first component, conjugated dienes such as butadiene, isoprene, and chloroprene can be used. Particularly, butadiene is preferably used.

As the monovinyl monomer as the second component of the copolymer used in the present invention, any monomer may be used if it has a single vinyl group. Preferred examples of the monovinyl monomer include (i) styrene, acrylonitrile, methyl methacrylate, vinyl chloride, vinyl acetate, and derivatives thereof, and 0i) alkyl acrylates, acrylamide, methacrylamide, acrolein, methacrolein, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, allyl acrylate, allyl methacrylate, N-methylolated acrylamide, N-methylolated methacrylamide, vinyl isocyanate and allyl isocyanate.

Examples of derivatives of styrene include methylstyrene, dimethylstyrene, ethylstyrene, 35 diethylstyrene, isopropyistyrene, butylstyrene, hexylstyrene, cyclohexylstyrene, decylstyrene, benzyistyrene, chloromethylstyrene, trifluoromethyistyrene, ethoxymethyistyrene, acetoxymethylstyrene, methoxystyrene, 4-methoxy-3-methyistyrene, dimethoxystyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4trifluoromethyistyrene, 4- 40 fluoro-3-trifluoromethyistyrene and methyl vinylbenzoate.

Preferred examples of the monomer described in (ii) above include acrylic acid esters, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate and 2- hydroxyethyl methacrylate.

Examples of the monomers having two or more vinyl groups, acryloyl groups, methaerylol groups or allyl groups in the molecule, which are the third component of the copolymer used in the 45 present invention include the so-called cross-linking agents which are added in polymerization of vinyl monomers, such as divinylbenzene, 1,5-hexadiene-3-yne, hexatriene, divinyl ether, divinyl sulfone, diallyl phthalate, diallyl carbinol, diethylene glycol and dimethacrylate, trymethylolpropane trimethacrylate and trimethylolpropane dimethacrylate.

A preferred content of the diolefin monomer (1) in the copolymer of the present invention is from 50 10% to 60% by weight, based on the total weight of the components (1) and (2), and more preferably is from 15% to 40% by weight.

A content of monovinyl monomer(s) (2) is preferably from 90% to 40% by weight, based on the total weight of the copolymer. However, it is particularly preferred that the above-described monovinyl monomers (i), and particularly styrene derivatives, be contained in the copolymer in a content of from 55 70% to 40% by weight based on the total weight of the components (1) and (2).

It is preferred that the monomer(s) (3) having two or more vinyl groups, acryloyl groups, methacryloyl groups, or allyl groups be contained in the copolymer in a content of from 0.01 % to 10% by weight, and more preferably from 0.1 % to 5% by weight, based on the total weight of the diolefin monomer (1) and the monovinyi monomer (2).

Examples of particularly preferred copolymers among the copolymers of the present invention include the following copolymers:

3 GB 2 077 745 A 3 Table 1

1 st Component 2nd Component 3rd Component (1) Butadiene 33 Styrene 67 Divinylbenzene 0.5 (2) Butadiene 25 Styrene 75 Divinylbenzene 0.5 (3) Butadiene 40 Styrene 60 Divinylbenzene 0.5 5 (4) Butadiene 33 Styrene 67 Divinylbenzene 0.1 (5) Butadiene 33 Styrene 67 Divinylbenzene 5 (6) Isoprene 33 Styrene 67 Divinylbenzene 0.5 (7) Butadiene 33 Methyl 67 Diviny[benzene 0.5 1.0 Methacrylate 10 (8) Butadiene 33 Acrylontrile 67 Divinyibenzene 0.5 (9) Butadiene 33 Chloromethyl- 67 Divinylbenzene 0.5 styrene (10) Butadiene 33 Styrene 67 Diethylene Glycol 0.5 Dimethacrylate 15 (11) Butadiene 33 Styrene 67 Trimethylolpropane 0.5 Trimethacrylate (12) Butadiene 33 Styrene 67 Diallyl Phthalate 0.5 In Table 1, the 1 st and 2nd component contents are indicated in % values, based upon the combined weights of the 1 st and 2nd components being considered as representing 100% of the weight, the 20 content of the 3rd component represents the % by weight of the 3rd component present based on the total weight of the 1 st and 2nd components.

Thus, it is characteristic of the present invention to use a latex of a copolymer composed of (1) a diolefin monomer, (2) at least one monovinyl monomer, and (3) at least one monomer having two or more vinyl groups, acryloyl groups, methacryloyl groups, or allyl groups excepting the diolefin monomer, wherein a gel fraction of the copolymer is from 50% to 95% by weight. Component (3) assists cross-linking of the polymer.

Herein, the term "gel" refers to a state wherein the copolymer components are three dimensionally polymerized. When the copolymer having the above-described composition is cross linked, i.e. polymerizes three-dimensionally, the solubility thereof in a solvent varies according to the 30 degree of the three-dimensional polymerization. The copolymer becomes more difficult to dissolve as the degree of three-dimensional polymerization increases.

Accordingly, the degree of three-dimensional polymerization of the gel can be determined by the solubility thereof. Since the solubility also depends upon the solvent used, definition of the degree of three-dimensional polymerization of the gel varies with the kind of the solvent used. More particularly, 35 then, in the present invention, the term "gel" refers to a three- dimensionally copolymerized state wherein the degree of three dimensional polymerization is such that the copolymer does not dissolve in purified tetrahydrofuran when immersed therein for 48 hours at 200C.

Accordingly, the expression "gel fraction" in the present invention means a value calculated with the following formula:

vi-W2 Gel Fraction (%)-x 100 wi wherein W, represents the weight of the copolymer in a sample, and W2 represents the weight of the solid content obtained by drying a filtrate which was obtained by filtering using a filter of 300 mesh after maintaining the sample in purified tetrahydrofuran at 201C for 48 hours, in vacuum at 20'C (i.e., W 2 refers to the weight of components of the copolymer dissolving in the tetrahydrofuran).

In the case of using a latex of a copolymer composed of a diolefin monomer and one or more monovinyl monomers as described in British Patent Application GB 2040730A wherein the gel fraction of the copolymer of said latex is less than 50% by weight, sufficient adhesive strength can be obtained, but there is a problem in that the surface of the subbing layer is easily scratched in the drying step after application. The state of the surface of the subbing layer deteriorates as the gel fraction decreases, 50 which is contrary to the practically desired adhesive strength in a wet state.

Surprisingly, it has now been found that, even if the gel fraction of the system is 50% by weight or more, adhesive strength equal to or higher than that obtained in the case of having a gel fraction of less than 50% by weight as described in British Patent Application GB 2040730A can be obtained by adding a monomer having two or more vinyl groups, acryloyl groups, methacryloyl groups or allyl groups (i.e., a cross-linking agent) to the copolymer composition.

Furthermore, it has surprisingly been found that sufficient adhesive strength in a wet state is obtained even if subjected to heat treatment at a low temperature, provided that the ethylenically unsaturated carboxylic acid component in the copolymer is 0%.

Though it is one of the characteristics of the present invention that the gel fraction of the copolymer is from 50% to 95% by weight, a gel fraction of from 60% to 90% by weight is more 4 GB 2 077 745 A 4 advantageous because of lessened deterioration of the subbing layer and superior adhesive strength.

Preparation of an aqueous dispersion of the copolymer used in the present invention can be made based on the descriptions of, for example, Goseigomu Gaisetsu (An Outline of Synthetic Rubber), pp.

39-59, written by Osami Asal (published by Asakura Shoten, 197 1), and Nippon Gomu Kyokaishi (Journal of the Society of RubberIndustry, Japan), Vol. 50, No. 12, pp 802-806 (1977).

Particularly, it is possible to prepare the polymer latex by emulsion copolymerization of the diolefin monomer and the monovinyl monomers in the presence of water, an emulsifier, a polymerization initiator, and a polymerization regulator (chain transfer agent), etc., as described, for example, in D.C. Blackley: High Polyrrer Science, Vol. 1, p. 294, Maclaren & Sons, Ltd., London.

As the emulsifier, it is possible to use, for example, aliphatic acid soaps and rhodinic acid soaps. 10.

The amount thereof is preferred to be in the range of from 0.1 to 5% by weight. As the polymerization initiator, it is possible to use, for example, peroxides, NaP04' 1 OH,O, K,S,0, p menthane hydroperoxide, FeS04. 7H20, and EDTA (ethylenediaminetetraacetic acid) tetrasodium salt.

As the polymerization regulator, it is possible to use, for example, primary and tertiary mereaptans having from 6 to 18 carbon atoms, for example, t- dodecyimercaptan, t-nonyimercaptan, 15 and t-decyimercaptan.

The amount of the polymerization regulator used is preferred to be in the range of from 0.05 to 2.0% by weight based on the total content of the latex. The polymerization regulator may be present in a reaction container prior to initiation of the polymerization reaction or may be added little by little during the polymerization reaction.

Further, in order to terminate the polymerization at a suitable stage, it is possible to use a polymerization terminator, such as hydroquinone or d i methylca rba mate. The polymerization terminator may be added at an optional stage at which the polymerization reaction has moderately proceeded, and the amount thereof is preferred to be about 0. 1 % by weight based on the total content of the latex.

As described above, a gel fraction of from 50% to 95% by weight is a characteristic of the present invention. A desired value of the gel fraction can be achieved by appropriately selecting the kind and the amount of the polymerization regulator in the emulsion polymerization reaction or by controlling the time of addition of the polymerization terminator.

Selection of the kind and the amount of the polymerization regulator or determination of the time 30 -of adding the polymerization terminator can be easily done by experimental means by persons skilled in the art in accordance with the foregoing general guidelines.

After the emulsion polymerization, unreacting monomers are, if desired, removed to obtain a latex of the copolymer according to the present invention. The removal can be carried out by the method described, for example, in Japanese Patent Publication 20075/74.

A concentration of the copolymer (as solid content) of the aqueous dispersion can be suitably decided. In general, it is preferred to be in the range of from 10% to 60% by weight, and more preferably from 30% to 50% by weight.

In order to apply the resulting aqueous dispersion of the copolymer used in the present invention as a subbing layer, the aqueous dispersion is diluted with water, and, if desired, a hardening agent, a 40 surface active agent, a swelling agent, a hydrophilic polymer, a matting agent, and an antistatic agent, are added thereto.

The content of the copolymer used in the present invention in the subbing solution is preferably in the range of from 1 to 10% by weight and more preferably 2% to 5% by weight.

As the hardening agent, there are, for example, triazine compounds as described in U.S. Patents 45 3,325,287, 3,288,775 and 3,549,377 and Belgian Patent 6,602,226, dialdehyde compounds as described in U.S. Patents 3,291,624 and 3,232,764, French Patent 1,543, 694 and British Patent 1,270,578, epoxy compounds as described in U.S. Patent 3,091,537 and Japanese Patent Publication 26580/74, vinyl compounds as described in U.S. Patent 3,642,486, aziridine compounds as described in U.S. Patent 3,392,024, ethyleneimine compounds as described in U.S. Patent 3,549,378, and 50 methylol compounds.

Among these hardening agents, 2,4-dichforo-6-hydroxy-s-triazine sodium salt is preferably used as the triazine compound. The amount of the hardening agent used is from 0.001 to 10 g per liter of the subbing solution.

As the swelling agent, there are, for example, phenol and resorcinol, though it is not necessary to 55 add them. An amount thereof is typically from 1 to 10 g per liter of the subbing solution.

As the hydrophilic polymer it is possible to use natural polymers, such as gelatin, and synthetic polymers, such as polyvinyl alcohol, vinyl acetate-maleic acid anhydride copolymer, acrylic acid acrylamide copolymer, and styrene-malelc acid anhydride copolymer. The amount thereof is preferred to be in the range of from 0.05 to 5 g, and more preferably from 0. 1 to 1 g.

As the matting agent, it is preferred to use silicon dioxide (Silica), polystyrene and polymethyl methacrylate, having an average particle size of from 0. 1 to 10 p.

As the antistatic agent, it is possible to use, for example, anionic surface active agents, cationic surface active agents, ionic polymers, maleic acid copolymers as described in Japanese Patent GB 2 077 745 A 5 Application (OPI) 3972/74, and colloidal silica (for example, Showtex (trademark) produced by Nissan Chemicals Ind. Co.).

The subbing solution according to the present invention can be applied by well known coating methods, for example, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method and a gravure coating method, or an extrusion coating method using a hopper described in U.S. Patent 2,681,294. If desired, two or more layers may - be applied at the same time by a method described in U.S. Patents 2,761, 791, 3,508,947, 2,941,898 and 3,526,528, and Coating Technology, p. 253, written by Harasaki et al. (published by Asakura Shoten Co., 1973).

1D The coating amount of the copolymer according to the present invention is preferably in a range 10 of from 0.0 1 to 10 g and more preferably from 0.2 to 3 g (solid content) per square meter of the plastic film base.

The subbing solution thus-coated is then dried in a drying step. The drying can be carried out by suitably selecting the temperature and the time within the ranges of from 1201C to 2001C and from 30 seconds to 10 minutes.

In the present invention, the expression "plastic film base- includes films comprising, for example, cellulose esters (particularly, cellulose triacetate, cellulose diacetate, and cellulose propionate), polyamides, polycarbonates, polyesters (particularly, polyethylene terephthalate, poly-11,4 cyclohexanedimethylene terephthalate, and polyethylene-1,2diphenoxyethane-4,4-dicarboxylate), polystyrenes, polypropylene or polyethylene, etc., and compound films prepared by coating or 20 laminating paper or another base with the abovedescribed film.

Among these plastic film bases, polyethyiene terephthalate films are the most suitable to use.

Particularly, biaxially stretched thermally set polyethylene terephthalate films are advantageously used in view of their stability and strength.

The thickness of the plastic film base is not particularly restricted. However, a thickness of from 25 to 500 A, and particularly from 40 to 200 u, is advantageous from the viewpoint of easy handling and common uses.

Further, the base may be transparent, may contain dyes, or may contain pigments such as titanium dioxide. Moreover, it may contain silicon dioxide, alumina sol, chromium salts, zirconium salts, etc.

To the base provided with the subbing layer according to the present invention, photographic layers are applied by conventional coating methods to produce a photographic light-sensitive material.

As the photographic layers, there are, for example, a silver halide emulsion layer, an intermediate layer, a filter layer, a surface protective layer and a backing layer.

These photographic layers contain a hydrophilic colloid as a binder. Examples of the hydrophilic 35 colloid include gelatin, phthalated gelatin, maleated gelatin, carboxymethyl cellulose, hydroxyethyl cellulose, grafted gelatin, polyvinyl alcohol, polyhydroxyalkyl acrylate, polyvinyl pyrrolidone and copoly vinyl pyrrolidone-vinyl acetate. Beside these hydrophilic colloids, they may contain a dispersion of a water-insoluble or poorly soluble synthetic polymer. For example, it is possible to use polymers composed of one or more of alkyl acrylates (or methacrylates), alkoxyalky acrylates (or methacrylates), 40 glycidyl acrylates (or methacrylates), acrylamide (or methacrylamide), vinyl esters (for example, vinyl acetate), acrylonitrile, olefins or styrene as monomer components.

In addition, the photographic layers may contain silver halide particles, chemical sensitizers, antifogging agents, stabilizers, hardening agents, antistatic agents, coating assistants, matting agents, whitening agents, spectral sensitizing dyes, dyes and color couplers, etc.

These additives are described in Research Disclosure, Vol. 92, pp. 107110 (Dec. 197 1).

In the following, the present invention is illustrated by reference to examples. However the present invention is not limited thereto.

Adhesion tests in examples were carried out by the following methods.

(1) Adhesion Test in a Dry State:

An emulsion surface of an unexposed nondeveloped dry film and that of a dried film after imagewise exposure and photographic development were scratched by a razor to form mesh scratches at intervals of about 4 mm. Then, an adhesive tape (Scotch Tape, registered Trade Mark produced by Sumitomo 3M Co.) was adhered to the emulsion surface and stripped off in an instant. The case wherein the stripped part was from 0% to 5% is shown as Grade A, the case wherein the stripped part 55 was from 5% to 30% is shown as Grade B, and the case wherein the stripped part was from 30% to 100% is shown as Grade C.

(2) Adhesion Test in a Wet State:

An emulsion surface of a film was scratched by a steel pen in a processing solution in a step of development, fixation or water wash to form two cross scratches. The scratched part was then rubbed 60 by a finger tip in a particular direction to the scratch lines. The case that the emulsion layer is not stripped is shown as Grade A. The case wherein the maximum stripping width was 5 mm or less is shown as Grade B, and the case wherein the maximum stripping width was larger than 5 mm is shown as Grade C.

6 GB 2 077 745 A 6 (3) Surface Scratch Test:

A subbing solution was applied to a 180 iu PET base, and subjected to drying and heat treatment at 1801C for 1 minute. In this case, with using a coater, the base was conveyed at 50 m/min so as to contact the surface of the subbing layer with a roll. Then, a test strip for observing the surface state (21 x30 cm) was removed from the base, and scratches formed are observed by transmitted light. The 5 case wherein no scratches were formed is shown as Grade A. The case wherein scratches were partially formed is shown as Grade B. The case wherein scratches were formed on the whole surface is shown as Grade C.

Example 1 10 A subbing solution having the following composition was applied to a 180 ju crystallized polyethylene terephthalate film which was biaxially stretched and orientated. It was then subjected to drying and heat treatment at 1801C for 1 minute to obtain a coated material having a dry subbing layer thickness of 0.5 M. To this base having a subbing layer, a silver halide emulsion for X-ray use (AgBri, 1=2.5% by mol) was applied so as to be 3 g of silver and 3.5 g of gelatin per square meter.

Subbing Composition (l):

Butadiene-styrene-diviny[benzene-acrylic acid copolymer latex (solid content: 50%; ratio by weight of butadlene/styrene=33/67; divinylbenzene content: 0.5% by weight based on the total amount of butadiene-styrene; acrylic acid content: 1 % by weight based on the total amount of butadiene-styrene; get fraction: 70% by weight) 8% Aqueous solution of2,4-dichloro-6-hydroxy-s-triazine sodium salt Distilled water Subbing Composition (2):

Butadiene-styrene-acrylic acid copolymer latex (solid content: 50%; ratio by weight of butadiene/styrene=33/67; acrylic acid content: 1 % based on the total amount of butadiene-styrene; gel fraction: 70% by weight) 8% Aqueous solution of 2,4-dichforo-6-hydroxy-striazine sodium salt 30 Distilled water Subbing Composition (3): Butadiene-styrene-acrylic acid copolymer latex (solid content: 50%; ratio by weight of butadiene/styrene=33/67; acrylic acid content: 1 % by weight based on the total amount of butadiene- styrene; gel fraction: 35 40%) 8% Aqueous solution of 2,4-dichloro-6- hydroxy-s-triazine sodium salt Distilled water Table 2 cc 2 cc 150 cc cc 2 cc cc 30 cc 35 2 cc cc Surface Subbing Adhesive Strength Adhesive Strength Scratch 40 Composition in Wet State in Dry State Test (1) Inv. A A A (2) B A A (3) A A C In the photographic light-sensitive films thus-obtained, the adhesive strength in a wet state was 45 Grade A in case of the subbing compositions (1) and (3), but was Grade B in case of the subbing composition (2). The adhesive strength in a dry state was Grade A in every case. In the surface scratch test, the subbing compositions (1) and (2) showed Grade A, but the subbing composition (3) showed Grade C. Furthermore, photographic properties of the photographic light- sensitive films were excellent in every case.

W Example 2

Subbing solutions having the subbing compositions (1), (2), and (3) as in Example 1, and the following subbing composition (4) were applied to a 180 p crystallized polyethylene terephthalate films which was biaxially stretched and orientated. They were then subjected to drying and heat treatment at 1600C for 1 minute to obtain a coated material having a dry subbing layer thickness of 55 0.5 ju. Thereafter, an emulsion was applied according to Example 1.

1 1 7 GB 2 077 745 A 7 Subbing Composition (4): Butadiene-styrene-divinyibenzene copolymer latex (solid content: 50%; ratio by weight of butadiene/styrene: 33/67; divinylbenzene content: 0.5% by weight based on the total amount of butadiene-styrene; gel 5 fraction: (70%) 8% Aqueous solution of 2,4- dichloro-6-hydroxy-s-triazine sodium salt Distilled water Table 3

Adhesive Adhesive Strength Strength Surface 10 Subbing in in Scratch Composition Wet State Dry State Test (1) B A A (2) c A A (3) B A c 15 (4) A A A cc 5 2 cc cc In the photographic light-sensitive films thus-obtained, the adhesive strength in a wet state was Grade A in the case of subbing composition (4), but it was Grade B in the case of the subbing compositions (1) and (3) and Grade C in case of the subbing composition (2). The adhesive strength in a dry state was Grade A in every case. In the surface scratch test, the subbing compositions (1), (2) and 20 (4) showed Grade A, but the subbing composition (3) showed Grade C. Furthermore, photographic properties of the photographic light-sensitive films were excellent in every case.

Claims

1. A process of subbing photographic light-sensitive film base, comprising applying to a plastics film base a latex of a copolymer derived from (1) a diolefin monomer, (2) at least one monovinyl monomer 25 and (3) at least one monomer having two or more vinyl groups, acryloyl groups, methacryloyl groups or ally] groups, other than diolefin monomer, wherein the proportion of the polymer in the latex which is cross-linked to be in a gel state (as herein defined as being insoluble in tetra hydrofu ran) is from 50% to 95% by weight.

2. A subbing process as claimed in Claim 1, wherein said diolefin monomer component (1) is 30 butadiene, isoprene or chloroprene.

3. A subbing process as claimed in Claim 1 or 2, wherein the monovinyl monomer (2) is styrene, acrylonitrile, methyl methacrylate, vinyl chloride, vinyl acetate or a derivative thereof.

4. A subbing process as claimed in Claim 1 or 2, wherein the monovinyl monomer (2) is an alkyl acrylate, acrylamide, methacryiamide, acrolein, methacrolein, g(ycidyl acrylate, giycidyl methacrylate, 35 2-hydroxyethyl acrylate, 2- hydroxyethyl methacrylate, allyl acrylate, allyl methacrylate, N- methylolated acrylamide, N-methylolated methacrylamide, vinyl isocyanate or allyl isocyanate.

5. A subbing process as claimed in Claim 1 or 2, wherein the monovinyl monomer (2) is methylstyrene, dimethylstyrene, ethylstyrene, di ethyl styrene,. isopropylstyrene, butylstyrene, hexylstyrene, cyclohexylstyrene, decylstyrene, benzyistyrene, chloromethylstyrene, trifluoromethylstyrene, ethoxymethyistyrene, acetoxymethylstyrene, methoxystyrene, 4-methoxy-3methyistyrene, dimethoxystyrene, chforostyrene, dichlorostyrene, trichiorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2bromo-4- trifluoromethylstyrene, 4-fluoro-3-trifluoromethyistyrene or methyl vinylbenzoate.

6. A subbing process as claimed in Claim 1 or 2, wherein the monovinyl monomer (2) is an acrylic 45 acid ester, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.

7. A subbing process as claimed in any preceding claims, wherein said monomer (3) is divinylbenzene, 1,5-hexadiene-3-yne, hexatriene, divinyl ether, divinyl sulfone, diallyi phthalate, diallyl carbino(, diethyiene glycol dimethacrylate, trimethylolpropane trimethacrylate or tri methylo 1pro pane 50 dimethacrylate.

8. A subbing process as claimed in any preceding claim, wherein the diolefin monomer (1) content is from 10% to 60% by weight, based on the total weight of components (1) and (2).

9. A subbing process as claimed in Claim 8, wherein said diolefin monomer component (1) content is from 15% to 40% by weight.

-

10. A subbing process as claimed in any preceding claim, wherein the monovinyl monomer component (2) content is from 90% to 40% by weight, based on the total weight of components (1) and (2).

11. A subbing process as claimed in Claim 10, wherein the component (2) is a polystyrene derivative which is present in a content of from 70% to 40% by weight, based on the total weight of 60 components (1) and (2).

12. A subbing process as claimed in any preceding claim, wherein the monomer component (3) content is from 0.01 % to 10% by weight, based on the total weight of the components (1) and (2).

8 GB 2 077 745 A 8

13. A subbing process as claimed in Claim 12, wherein the monomer component (3) content is 0. 1 % to 5% by weight.

14. A subbing process as claimed in any preceding claim, wherein the gel fraction of the polymer in the latex is from 60% to 90% by weight.

15. A subbing process as claimed in any preceding claim, wherein the copolymer constitutes from 5 10% to 60% by weight of the polymer latex.

16. A subbing process as claimed in claim 15, wherein the copolymer constituted from 30% to 50% by weight of the polymer latex.

17. A subbing process as claimed in any preceding claim, wherein the copolymer is coated in an amount of from 0.01 to 20 grams (solid content) per square metre of the plastic film base.

18. A subbing process as claimed in Claim 17, wherein the coated amount is from 0.2 to 3 g per square metre.

19. A subbing process as claimed in any preceding claim, wherein the plastic film base is of polyethylene terephthalate.

20. A subbing process as claimed in Claim 1, substantially as hereinbefore described with 15 reference to Sample (1) or (4) of the Examples.

2 1. A subbed plastic film base when prepared by a process as claimed in any preceding claim.

22. A photographic light-sensitive material which includes a subbed base as claimed in Claim 2 1.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1981. Published by the Patent Office, 25 Southampton Buildings, London, WC2A l AY, from which copies maybe obtained.

0